(8)
Contents
Page
Contents   (8)
List of Tables   (10)
List of Figures   (11)
Chapter
1. Introduction   1
Literature review
Browning reaction   3
1. Enzymatic browning reaction   3
2.   Non-enzymatic browning reaction   12
3.   The control of enzymatic browning   25
Objectives   33
2.Materials and methods   34
1. Chemicals   34
2. Instruments   35
3.   Methods   35
3.1. Extraction of black tiger prawn PO   35
3.2. Characterization of black tiger prawn PO   36
3.3. Effect of cysteine concentration on the PO activity   37
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Contents (Continued)
Page
3.4. Effect of types of amino acid and sugar
in model system on inhibition of PO     38
3.5. Effect of heating time of fructose/glycine
model system on inhibition of PO   41
3.6. Effect of temperature on the PO inhibitory activity
of MRPs from fructose/glycine model system   42
3.7. Effect of reactant concentration of
fructose/glycine model system on inhibition of PO   42
3.8. Effect of pHs of fructose/glycine model system
on inhibition of PO   43
3.9. Decolorization of fructose/glycine MRPs   43
3.10. Effect of MRPs on changes in chemical and
sensory properties of black tiger prawn during iced storage   44
4. Statistical analysis   46
3. Result and discussion   47
4. Conclusion   121
References   123
Appendix   147
Vitae   153
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List of Tables
Table Page
1. Characteristic of PO from crustaceans   8
2. Effect of chemicals on black tiger prawn PO activity   54
(11)
List of Figures
Figure Page
1. Coordination of copper to six histidine residues in active site of PO   4
2. Enzymatic oxidation induced by PO   5
3. Scheme of Maillard reaction   14
4. Formation of Amadori compound from glucose and amine   16
5. Scheme of advanced Maillard reaction from glucose/glycine.
AMP (Advanced Maillard Products)   17
6. Selected sugar degradation reaction   24
7. pH and temperature profile of black tiger prawn PO activity   49
8. pH and temperature stability of  black tiger prawn PO activity   51
9. Inhibitory activity of cysteine with various concentrations
towards PO from black tiger prawn    55
10. Changes in pH of MRPs derived from various amino acids and
reducing sugars at the  concentrations of 0.5 or 0.75 mM heated
at 100?C for 8 h.     56
11. Changes in fluorescence intensity, A
294
 and A
420
 of MRPs derived
from various amino acids and reducing sugars at the  concentrations
of 0.5 or 0.75 mM heated at 100?C for 8 h.   58
12. The loss of reducing sugar and free amino group contents of MRPs
derived from various amino acids and reducing sugars at the
concentrations of 0.5 or 0.75 mM heated at 100?C for 8 h.   60
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List of Figures (Continued)
Figure Page
13. Reducing power of MRPs derived from various amino acids and
 reducing sugars at the  concentrations of 0.5 or 0.75 mM
 heated at 100?C for 8 h.     62
14. Copper chelating property of MRPs derived from various amino acids
and reducing sugars at the concentrations of 0.5 or 0.75 mM
heated at 100?C for 8 h.   63
15. Inhibitory activity towards black tiger prawn PO of MRPs derived
from various amino acids and reducing sugars at the concentrations
of 0.5 or 0.75 mM heated at 100?C for 8 h.     65
16. Changes in pH of fructose/glycine MRPs prepared  with  various
heating times  at 100 ?C.   66
17. Changes in fluorescence intensity, A
294
 and A
420
 of fructose/glycine
MRPs prepared  with  various heating times at 100 ?C.   68
18. The loss of reducing sugar and free amino group contents of
fructose/glycine MRPs prepared  with  various heating times at 100 ?C.  70
19. Reducing power of fructose/glycine MRPs prepared  with  various
heating times at 100 ?C.   71
20. Copper chelating property of fructose/glycine MRPs prepared  with
various heating times at 100 ?C.   72
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List of Figures (Continued)
Figure Page
21. Inhibitory activity towards black tiger prawn PO of fructose/glycine
MRPs prepared  with  various heating times at 100 ?C.    74
22. Changes in pH of fructose/glycine MRPs prepared  with  various
heating temperatures for 12 h.   75
23. Changes in fluorescent intensity, A
294
 and A
420
 of fructose/glycine
MRPs prepared  with  various heating temperatures for 12 h.   77
24. The loss of reducing sugar and free amino group contents of
fructose/glycine MRPs prepared  with  various heating
temperatures for 12 h.   79
25. Reducing power of fructose/glycine MRPs prepared  with  various
heating  temperatures for 12 h.   80
26. Copper chelating property of fructose/glycine MRPs prepared  with
various heating temperatures for 12 h.   81
27. Inhibitory activity towards black tiger prawn PO of fructose/glycine
MRPs prepared  with  various heating temperatures for 12 h.   82
28. Changes in pH of fructose/glycine MRPs prepared  with  various
reactant concentrations at 100 ?C for 12 h.   83
29. Changes in fluorescent intensity, A
294
 and A
420
 of fructose/glycine
MRPs prepared  with  various concentrations for 12 h.   86
30. Changes in A
294
/A
420
 of fructose-glycine MRPs prepared  with
various reactant concentrations at 100 ?C for 12 h.   87
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List of Figures (Continued)
Figure Page
31. The loss of reducing sugar and free amino group content of
fructose/glycine MRPs prepared  with  various reactant
concentrations at 100 ?C for 12 h.   90
32. Reducing power of fructose/glycine MRPs prepared  with
various reactant concentrations at 100 ?C for 12 h.   91
33. Copper chelating property of fructose-glycine MRPs prepared
with  various reactant concentrations at 100 ?C for 12 h.   92
34. Inhibitory activity towards black tiger prawn PO of fructose/glycine
MRPs prepared  with  various reactant concentrations
at 100 ?C for 12 h.     94
35. Changes in pH of fructose/glycine MRPs prepared  with  various
initial pHs at 100 ?C for 12 h.   95
36. Changes in fluorescence intensity, A
294
 and A
420
 of
fructose/glycine MRPs prepared  with  various initial pHs
at 100 ?C for 12 h.   98
37. The loss of reducing sugar and free amino group contents of
fructose/glycine MRPs prepared with various initial
pHs at 100 ?C for 12 h.   100
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List of Figures (Continued)
Figure Page
38. Reducing power of fructose/glycine MRPs prepared  with  various
initial pHs at 100 ?C for 12 h.   101
39. Copper chelating property of fructose/glycine MRPs prepared
with  various initial pHs at 100 ?C for 12 h.   102
40. Inhibitory activity towards black tiger prawn PO of fructose/glycine
MRPs prepared  with  various initial pHs at 100 ?C for 12 h.   103
41. L*, a*, b*-values of MRPs and MRPs decolorized by activated
carbon or Sep-Pak Cartridge C18.   105
42. Browning intensity, A
294 
and fluorescence intensity of MRPs
decolorized by activated carbon and Sep-Pak Cartridge C18.   107
43. Reducing power of MRPs decolorized by activated carbon and
Sep-Pak Cartridge C18.   109
44. Copper chelating property of MRPs decolorized by activated
carbon and Sep-Pak Cartridge C18.   111
45. PO inhibitory activity of MRPs decolorized by activated carbon
and Sep-Pak Cartridge C18.   112
46. Changes in pH of black tiger prawn muscle treated with
MRPs or Na-metabisulfite during iced storage.   114
47. Changes in TVB content of black tiger prawn muscles
treated with MRPs or Na- metabisulfite during iced storage.   116
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List of Figures (Continued)
Figure Page
48. Changes in melanosis score of black tiger prawn treated
with MRPs or Na-metabisulfite during iced storage.   118
49. Changes in sensory property of black tiger prawn treated
with MRPs or Na-metabisulfite during iced storage.   120